Test on Xenial Before: Last login: Wed Aug 15 19:29:38 2018 from 192.168.122.1 $ uname -a Linux bionic 4.4.0-133-generic #159-Ubuntu SMP Fri Aug 10 07:31:43 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux $ echo 9 | sudo tee /proc/sys/kernel/printk 9 $ sudo losetup --find --show --partscan rlv_grkgld.1mb [ 309.251832] partition (null) (21 pp's found) is not contiguous [ 309.254557] partition (null) (2 pp's found) is not contiguous [ 309.256893] partition (null) (1 pp's found) is not contiguous ... [ 309.335870] partition (null) (2 pp's found) is not contiguous [ 309.338133] partition (null) (64 pp's found) is not contiguous [ 309.339719] partition (null) (1 pp's found) is not contiguous [ 309.345218] BUG: unable to handle kernel paging request at 0000000000001040 [ 309.347776] IP: [] strnlen+0x9/0x40 [ 309.349813] PGD 0 [ 309.350719] Oops: 0000 [#1] SMP [ 309.351987] Modules linked in: isofs kvm_intel kvm irqbypass input_leds joydev serio_raw sch_fq_codel ib_iser rdma_cm iw_cm ib_cm ib_sa ib_mad ib_core ib_addr iscsi_tcp libiscsi_tcp libiscsi scsi_transport_i scsi ip_tables x_tables autofs4 btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor as ync_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear psmouse floppy [ 309.367248] CPU: 1 PID: 979 Comm: losetup Not tainted 4.4.0-133-generic #159-Ubuntu [ 309.369461] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 [ 309.372403] task: ffff880039a78000 ti: ffff88003b2f0000 task.ti: ffff88003b2f0000 [ 309.375267] RIP: 0010:[] [] strnlen+0x9/0x40 [ 309.377806] RSP: 0018:ffff88003b2f3830 EFLAGS: 00010086 [ 309.379278] RAX: ffffffff81cd2b01 RBX: ffffffff8211eb6c RCX: 0000000000000000 [ 309.381360] RDX: 0000000000001040 RSI: ffffffffffffffff RDI: 0000000000001040 [ 309.384074] RBP: ffff88003b2f3830 R08: 000000000000ffff R09: 000000000000ffff [ 309.385894] R10: ffff88003b2f39e8 R11: 0000000000000251 R12: 0000000000001040 [ 309.387906] R13: ffffffff8211ef40 R14: 00000000ffffffff R15: 0000000000000000 [ 309.389937] FS: 00007f7e0163c740(0000) GS:ffff88003fc80000(0000) knlGS:0000000000000000 [ 309.392496] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 309.394040] CR2: 0000000000001040 CR3: 0000000039a48000 CR4: 0000000000000670 [ 309.396505] Stack: [ 309.397306] ffff88003b2f3868 ffffffff8140d8cb ffffffff8211eb6c ffffffff8211ef40 [ 309.400370] ffff88003b2f3980 ffffffff81d00816 ffffffff81d00816 ffff88003b2f38d8 [ 309.403210] ffffffff8140f385 0000000000000092 0000000000000092 000000000000000c [ 309.406231] Call Trace: [ 309.407114] [] string.isra.4+0x3b/0xd0 [ 309.408818] [] vsnprintf+0x135/0x530 [ 309.410869] [] vscnprintf+0xd/0x30 [ 309.412283] [] vprintk_emit+0x123/0x520 [ 309.413983] [] vprintk_default+0x29/0x40 [ 309.415495] [] printk+0x5a/0x76 [ 309.417463] [] aix_partition+0x5d1/0x600 [ 309.419595] [] ? pagecache_get_page+0x2d/0x1c0 [ 309.421218] [] msdos_partition+0x86b/0x880 [ 309.423173] [] ? blkdev_readpages+0x20/0x20 [ 309.424963] [] ? read_cache_page+0x19/0x20 [ 309.426515] [] ? read_dev_sector+0x2d/0x90 [ 309.428280] [] ? snprintf+0x49/0x60 [ 309.429707] [] ? parse_solaris_x86+0x210/0x210 [ 309.432081] [] check_partition+0x140/0x220 [ 309.433845] [] rescan_partitions+0xbb/0x2b0 [ 309.435421] [] ? security_capable+0x4e/0x70 [ 309.437006] [] __blkdev_reread_part+0x65/0x70 [ 309.438598] [] blkdev_reread_part+0x23/0x40 [ 309.440173] [] loop_reread_partitions+0x28/0x50 [ 309.442811] [] loop_set_status+0x39a/0x3d0 [ 309.444381] [] loop_set_status64+0x50/0x70 [ 309.446146] [] lo_ioctl+0xf1/0x8b0 [ 309.447547] [] blkdev_ioctl+0x25e/0x910 [ 309.449056] [] ? __fd_install+0x33/0xe0 [ 309.451395] [] block_ioctl+0x3d/0x50 [ 309.453275] [] do_vfs_ioctl+0x2af/0x4b0 [ 309.455019] [] ? putname+0x54/0x60 [ 309.456434] [] ? do_sys_open+0x1bf/0x2a0 [ 309.457943] [] SyS_ioctl+0x79/0x90 [ 309.459886] [] entry_SYSCALL_64_fastpath+0x22/0xc1 [ 309.462722] Code: 00 00 80 3f 00 55 48 89 e5 74 11 48 89 f8 48 83 c0 01 80 38 00 75 f7 48 29 f8 5d c3 31 c0 5d c3 66 90 55 48 85 f6 48 89 e5 74 2e <80> 3f 00 74 29 48 8d 57 01 48 8d 04 37 eb 0d 48 8d 4a 01 8 0 79 [ 309.475971] RIP [] strnlen+0x9/0x40 [ 309.477537] RSP [ 309.478624] CR2: 0000000000001040 [ 309.479703] ---[ end trace 4fe99281b613609c ]--- After: $ uname -a Linux bionic 4.4.0-133-generic #159+sf181954.1 SMP Wed Aug 15 14:18:05 -03 2018 x86_64 x86_64 x86_64 GNU/Linux $ echo 9 | sudo tee /proc/sys/kernel/printk 9 $ sudo losetup --find --show --partscan rlv_grkgld.1mb /dev/loop0